 A lot of them have a thumb release on it, the cheaper guns. And if there's pressure, sometimes it's hard to get that to pop off of there, especially as the gun gets older. So the skeleton guns are the best. And we call them that because they don't have a lot of metal there. It just has a strip on the top and the bottom. And you can see the caulk tube almost 360 degrees except for one little stripe. So that's why they call it a skeleton.